Ultrasonic treatment chamber for preparing emulsions

ABSTRACT

An ultrasonic mixing system having a treatment chamber in which at least two separate phases can be mixed to prepare an emulsion is disclosed. Specifically, at least one phase is a dispersed phase and one phase in a continuous phase. The treatment chamber has an elongate housing through which the phases flow longitudinally from a first inlet port and a second inlet port, respectively, to an outlet port thereof. An elongate ultrasonic waveguide assembly extends within the housing and is operable at a predetermined ultrasonic frequency to ultrasonically energize the phases within the housing. An elongate ultrasonic horn of the waveguide assembly is disposed at least in part intermediate the inlet and outlet ports, and has a plurality of discrete agitating members in contact with and extending transversely outward from the horn intermediate the inlet and outlet ports in longitudinally spaced relationship with each other. The horn and agitating members are constructed and arranged for dynamic motion of the agitating members relative to the horn at the predetermined frequency and to operate in an ultrasonic cavitation mode of the agitating members corresponding to the predetermined frequency and the phases being mixed in the chamber.

FIELD OF DISCLOSURE

The present disclosure relates generally to systems for ultrasonicallymixing various phases to prepare an emulsion. More particularly anultrasonic mixing system is disclosed for ultrasonically mixing at leasta first phase and a second phase to prepare an emulsion.

BACKGROUND OF DISCLOSURE

Many currently used products consist of one or more emulsions.Specifically, there is a large array of cosmetic emulsions utilized forapplication of skin health benefits to the skin, hair, and body of auser. Additionally, many other emulsions are used to provide benefits toinanimate objects such as, for example, cleaning countertops, glass, andthe like. Generally, emulsions consist of a dispersed phase and acontinuous phase and are generally formed with the addition of asurfactant or a combination of surfactants with varyinghydrophilic/lipopilic balances (HLB). Although emulsions are useful,current mixing procedures have multiple problems, which can waste time,energy, and money for manufacturers of these emulsions.

Specifically, emulsions are currently prepared in a batch-type process,either by a cold mix or a hot mix procedure. The cold mix proceduregenerally consists of multiple ingredients or phases being added into akettle in a sequential order with agitation being applied via a blade,baffles, or a vortex. The hot mix procedure is conducted similarly tothe cold mix procedure with the exception that the ingredients or phasesare generally heated above room temperature, for example to temperaturesof from about 40 to about 100° C., prior to mixing, and are then cooledback to room temperature after the ingredients and phases have beenmixed. In both procedures, the various phases are added manually by oneof a number of methods including dumping, pouring, and/or sifting.

These conventional methods of mixing phases into emulsions have severalproblems. For example, as noted above, all phases are manually added ina sequential order. Prior to adding the phases, the ingredients for eachphase need to be weighed, which can create human error. Specifically, asthe ingredients need to be weighed one at a time, misweighing can occurwith the additive amounts. Furthermore, by manually adding theingredients, there is a risk of spilling or of incomplete transfers ofthe ingredients from one container to the next.

One other major issue with conventional methods of mixing phases toprepare emulsions is that batching processes (e.g., cold and hot mixprocedures described above) require heating times, mixing times, andadditive times that are entirely manual and left up to the individualcompounders to follow the instructions. These practices can lead toinconsistencies from batch-to-batch and from compounder to compounder.Furthermore, these procedures required several hours to complete, whichcan get extremely expensive.

Based on the foregoing, there is a need in the art for a mixing systemthat provides ultrasonic energy to enhance the mixing of two or morephases into emulsions. Furthermore, it would be advantageous if thesystem could be configured to enhance the cavitation mechanism of theultrasonics, thereby increasing the probability that the phases will beeffectively mixed to form the emulsions.

SUMMARY OF DISCLOSURE

In one aspect, an ultrasonic mixing system for mixing at least twophases to prepare an emulsion generally comprises a treatment chambercomprising an elongate housing having longitudinally opposite ends andan interior space. The housing is generally closed at at least one ofits longitudinal ends and has at least a first inlet port for receivingat least a first phase into the interior space of the housing, and asecond inlet port for receiving at least a second phase into theinterior space of the housing, and at least one outlet port throughwhich an emulsion is exhausted from the housing following ultrasonicmixing of the first and second phases. The outlet port is spacedlongitudinally from the first and second inlet ports such that liquid(i.e., first and/or second phases) flows longitudinally within theinterior space of the housing from the first and second inlet ports tothe outlet port. In one embodiment, the housing includes more than twoseparate ports for receiving additional phases to be mixed to preparethe emulsion. At least one elongate ultrasonic waveguide assemblyextends longitudinally within the interior space of the housing and isoperable at a predetermined ultrasonic frequency to ultrasonicallyenergize and mix the first and second phases (and any additional phases)flowing within the housing.

The waveguide assembly generally comprises an elongate ultrasonic horndisposed at least in part intermediate the first and second inlet portsand the outlet port of the housing and has an outer surface located forcontact with the first and second phases flowing within the housing fromthe first and second inlet ports to the outlet port. A plurality ofdiscrete agitating members are in contact with and extend transverselyoutward from the outer surface of the horn intermediate the first andsecond inlet ports and the outlet port in longitudinally spacedrelationship with each other. The agitating members and the horn areconstructed and arranged for dynamic motion of the agitating membersrelative to the horn upon ultrasonic vibration of the horn at thepredetermined frequency and to operate in an ultrasonic cavitation modeof the agitating members corresponding to the predetermined frequencyand the first and second phases being mixed within the chamber.

As such the present disclosure is directed to an ultrasonic mixingsystem for preparing an emulsion. The mixing system comprises atreatment chamber comprising an elongate housing having longitudinallyopposite ends and an interior space, and an elongate ultrasonicwaveguide assembly extending longitudinally within the interior space ofthe housing and being operable at a predetermined ultrasonic frequencyto ultrasonically energize and mix a first and a second phase flowingwithin the housing to prepare the emulsion. The housing is closed at atleast one of its longitudinal ends and has at least a first inlet portfor receiving a first phase into the interior space of the housing, anda second inlet port for receiving a second phase into the interior spaceof the housing, and at least one outlet port through which an emulsionis exhausted from the housing following ultrasonic mixing of the firstand second phases. The outlet port is spaced longitudinally from thefirst and second inlet ports such that the first and second phases flowlongitudinally within the interior space of the housing from the firstand second inlet ports to the outlet port.

The waveguide assembly comprises an elongate ultrasonic horn disposed atleast in part intermediate the first and second inlet ports and theoutlet port of the housing and having an outer surface located forcontact with the first and second phases flowing within the housing fromthe first and second inlet ports to the outlet port. Additionally, thewaveguide assembly comprises a plurality of discrete agitating membersin contact with and extending transversely outward from the outersurface of the horn intermediate the first and second inlet ports andthe outlet port in longitudinally spaced relationship with each other.The agitating members and the horn are constructed and arranged fordynamic motion of the agitating members relative to the horn uponultrasonic vibration of the horn at the predetermined frequency and tooperate in an ultrasonic cavitation mode of the agitating memberscorresponding to the predetermined frequency and the first and secondphases being mixed in the chamber.

The present invention is further directed to an ultrasonic mixing systemfor preparing an oil-in-water emulsion. The mixing system comprises atreatment chamber comprising an elongate housing having longitudinallyopposite ends and an interior space, and an elongate ultrasonicwaveguide assembly extending longitudinally within the interior space ofthe housing and being operable at a predetermined ultrasonic frequencyto ultrasonically energize and mix an oil phase and a water phaseflowing within the housing. The housing is generally closed at at leastone of its longitudinal ends and has at least a first inlet port forreceiving the oil phase into the interior space of the housing, and asecond inlet port for receiving the water phase into the interior spaceof the housing, and at least one outlet port through which anoil-in-water emulsion is exhausted from the housing following ultrasonicmixing of the oil phase and water phase. The outlet port is spacedlongitudinally from the first and second inlet ports such that the oiland water phases flow longitudinally within the interior space of thehousing from the first and second inlet ports to the outlet port.

The waveguide assembly comprises an elongate ultrasonic horn disposed atleast in part intermediate the first and second inlet ports and theoutlet port of the housing and having an outer surface located forcontact with the oil and water phases flowing within the housing fromthe first and second inlet ports to the outlet port; a plurality ofdiscrete agitating members in contact with and extending transverselyoutward from the outer surface of the horn intermediate the first andsecond inlet ports and the outlet port in longitudinally spacedrelationship with each other; and a baffle assembly disposed within theinterior space of the housing and extending at least in parttransversely inward from the housing toward the horn to directlongitudinally flowing oil and water phases in the housing to flowtransversely inward into contact with the agitating members. Theagitating members and the horn are constructed and arranged for dynamicmotion of the agitating members relative to the horn upon ultrasonicvibration of the horn at the predetermined frequency and to operate inan ultrasonic cavitation mode of the agitating members corresponding tothe predetermined frequency and the oil phase and water phase beingmixed in the chamber.

The present disclosure is further directed to a method for preparing anemulsion using the ultrasonic mixing system described above. The methodcomprises delivering the first phase via the first inlet port into theinterior space of the housing; delivering the second phase via thesecond inlet port into the interior space of the housing; andultrasonically mixing the first and second phases via the elongateultrasonic waveguide assembly operating in the predetermined ultrasonicfrequency.

Other features of the present disclosure will be in part apparent and inpart pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of an ultrasonic mixing system according to afirst embodiment of the present disclosure for preparing an emulsion.

FIG. 2 is a schematic of an ultrasonic mixing system according to asecond embodiment of the present disclosure for preparing an emulsion.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DETAILED DESCRIPTION

With particular reference now to FIG. 1, in one embodiment, anultrasonic mixing system, generally indicated at 121, for mixing phasesto prepare an emulsion generally comprises a treatment chamber,indicated at 151, that is operable to ultrasonically mix various phasesto form an emulsion, and further is capable of creating a cavitationmode that allows for better mixing within the housing of the chamber151.

It is generally believed that as ultrasonic energy is created by thewaveguide assembly, increased cavitation of the phases occurs, creatingmicrobubbles. As these microbubbles then collapse, the pressure withinthe chamber is increased forcibly mixing the various phases to form anemulsion.

The terms “liquid” and “emulsion” are used interchangeably to refer to aformulation comprised of two or more phases, typically one phase being adispersed phase and one phase being a continuous phase. Furthermore, atleast one of the phases is a liquid such as a liquid-liquid emulsion, aliquid-gas emulsion, or a liquid emulsion in which particulate matter isentrained, or other viscous fluids.

The ultrasonic mixing system 121 is illustrated schematically in FIG. 1and further described herein with reference to use of the treatmentchamber 151 in the ultrasonic mixing system to mix various phases tocreate an emulsion. The emulsion can be a cosmetic emulsion forproviding one of a variety of skin benefits to a user's skin, hair,and/or body. For example, in one embodiment, the cosmetic emulsion canbe an oil-in-water emulsion for cleansing the user's skin. It should beunderstood by one skilled in the art, however, that while describedherein with respect to oil-in-water emulsions, the ultrasonic mixingsystem can be used to mix various phases to prepare other types ofemulsions without departing from the scope of the present disclosure.For example, other suitable emulsions can include water-in-oilemulsions, water-in-oil-in-water emulsions, oil-in-water-in-oilemulsions, water-in-silicone emulsions, water-in-silicone-in-wateremulsions, glycol-in-silicone emulsions, high internal phase emulsions,and the like. Still other emulsions produced using the ultrasonictreatment system of the present disclosure include hand sanitizers,anti-aging lotions, wound care serums, teeth whitening gels, animate andinanimate surface cleansers, wet wipe solutions, suntan lotions, paints,inks, coatings, and polishes for both industrial and consumer products.

In one particularly preferred embodiment, as illustrated in FIG. 1, thetreatment chamber 151 is generally elongate and has a general inlet end125 (a lower end in the orientation of the illustrated embodiment) and ageneral outlet end 127 (an upper end in the orientation of theillustrated embodiment). The treatment chamber 151 is configured suchthat at least two phases enter the treatment chamber 151 generally atthe inlet end 125 thereof, flow generally longitudinally within thechamber (e.g., upward in the orientation of illustrated embodiment) andexit the chamber generally at the outlet end 127 of the chamber.

The terms “upper” and “lower” are used herein in accordance with thevertical orientation of the treatment chamber 151 illustrated in thevarious drawings and are not intended to describe a necessaryorientation of the chamber in use. That is, while the chamber 151 ismost suitably oriented vertically, with the outlet end 127 of thechamber above the inlet end 125 as illustrated in the drawing, it shouldbe understood that the chamber may be oriented with the inlet end abovethe outlet end and the two phases are mixed as they travel downwardthrough the chamber, or it may be oriented other than in a verticalorientation and remain within the scope of this disclosure. Furthermore,it s

The terms “axial” and “longitudinal” refer directionally herein to thevertical direction of the chamber 151 (e.g., end-to-end such as thevertical direction in the illustrated embodiment of FIG. 1). The terms“transverse”, “lateral” and “radial” refer herein to a direction normalto the axial (e.g., longitudinal) direction. The terms “inner” and“outer” are also used in reference to a direction transverse to theaxial direction of the treatment chamber 151, with the term “inner”referring to a direction toward the interior of the chamber and the term“outer” referring to a direction toward the exterior of the chamber.

The inlet end 125 of the treatment chamber 151 is typically in fluidcommunication with at least one suitable delivery system that isoperable to direct one phase to, and more suitably through, the chamber151. More specifically, as illustrated in FIG. 1, two delivery systems128 and 129 are operable to direct a first phase (not shown) and asecond phase (not shown) through the chamber 151. Typically, thedelivery systems 128, 129 may independently comprise one or more pumps170 and 171, respectively, operable to pump the respective phases fromcorresponding sources thereof to the inlet end 125 of the chamber 151via suitable conduits 132, 134.

It is understood that the delivery systems 128, 129 may be configured todeliver more than one phase to the treatment chamber 151 withoutdeparting from the scope of this disclosure. It is also contemplatedthat delivery systems other than that illustrated in FIG. 1 anddescribed herein may be used to deliver one or more phases to the inletend 125 of the treatment chamber 151 without departing from the scope ofthis disclosure. It should be understood that more than one phase canrefer to two streams of the same phase or different phases beingdelivered to the inlet end of the treatment chamber without departingfrom the scope of the present disclosure.

The treatment chamber 151 comprises a housing defining an interior space153 of the chamber 151 through which at least two phases delivered tothe chamber 151 flow from the inlet end 125 to the outlet end 127thereof. The chamber housing 151 suitably comprises an elongate tube 155generally defining, at least in part, a sidewall 157 of the chamber 151.The tube 155 may have one or more inlet ports (two inlet ports aregenerally indicated in FIG. 1 at 156 and 158) formed therein throughwhich at least two separate phases to be mixed within the chamber 151are delivered to the interior space 153 thereof. It should be understoodby one skilled in the art that the inlet end of the housing may includemore than two inlet ports, more than three ports, and even more thanfour ports. By way of example, although not shown, the housing maycomprise three inlet ports, wherein the first inlet port and the secondinlet port are suitably in parallel, spaced relationship with eachother, and the third inlet port is oriented on the opposite sidewall ofthe housing from the first and second inlet ports.

It should also be recognized by one skilled in the art that, whilepreferably the inlet ports are disposed in close proximity to oneanother in the inlet end, the inlet ports may be spaced farther alongthe sidewall of the chamber from one another (see FIG. 2) withoutdeparting from the scope of the present disclosure. Specifically, asillustrated in FIG. 2, the first inlet port 228 is disposed at theterminus of the inlet end, generally indicated at 211, and the secondinlet port 229 is disposed longitudinally between the inlet end 225 andthe outlet end 227. This type of configuration is beneficial when one ormore of the phases to be mixed are reactive or potentially unstable dueto turbulence, heat, or interaction with another phase or component.These reactive components and/or phases can be added at an alternativepoint (i.e., a second inlet port) located away from the first inletport. In an alternative embodiment, the reactive component and/or phasecan be added outside of the chamber such as via an in-line mixer to theprepared emulsion once the emulsion exits the chamber.

Referring back to FIG. 1, the housing 151 comprises a closure connectedto and substantially closing the longitudinally opposite end of thesidewall 157, and having at least one outlet port 165 therein togenerally define the outlet end 127 of the treatment chamber.Alternatively, the housing comprises a closure connected to andsubstantially closing the longitudinally end of the side wall and havingat least one inlet port 228 (see FIG. 2) without departing from thescope of the present disclosure. The sidewall (e.g., defined by theelongate tube) of the chamber has an inner surface that together withthe waveguide assembly (as described below) and the closure define theinterior space of the chamber.

In the illustrated embodiment of FIG. 1, the tube 155 is generallycylindrical so that the chamber sidewall 157 is generally annular incross-section. However, it is contemplated that the cross-section of thechamber sidewall 157 may be other than annular, such as polygonal oranother suitable shape, and remains within the scope of this disclosure.The chamber sidewall 157 of the illustrated chamber 151 is suitablyconstructed of a transparent material, although it is understood thatany suitable material may be used as long as the material is compatiblewith the phases being mixed within the chamber, the pressure at whichthe chamber is intended to operate, and other environmental conditionswithin the chamber such as temperature.

A waveguide assembly, generally indicated at 203, extends longitudinallyat least in part within the interior space 153 of the chamber 151 toultrasonically energize the phases (and their resulting-emulsions)flowing through the interior space 153 of the chamber 151. Inparticular, the waveguide assembly 203 of the illustrated embodimentextends longitudinally from the lower or inlet end 125 of the chamber151 up into the interior space 153 thereof to a terminal end 113 of thewaveguide assembly disposed intermediate the inlet port (e.g., inletport 156 where it is present) and outlet port (e.g., outlet port 165where it is present). Although illustrated in FIG. 1 as extendinglongitudinally from the inlet end into the interior space 153 of thechamber 151, it should be understood by one skilled in the art that thewaveguide assembly may extend longitudinally from the outlet enddownward into the interior space (see FIG. 2); that is the waveguideassembly may be inverted within the chamber housing without departingfrom the scope of the present disclosure. Additionally, the waveguideassembly may extend laterally from a housing sidewall of the chamber,running horizontally through the interior space thereof withoutdeparting from the scope of the present disclosure. Typically, thewaveguide assembly 203 is mounted, either directly or indirectly, to thechamber housing 151 as will be described later herein.

Still referring to FIG. 1, the waveguide assembly 203 suitably comprisesan elongate horn assembly, generally indicated at 133, disposed entirelywith the interior space 153 of the housing 151 intermediate the inletports 156, 158 and the outlet port 165 for complete submersion withinthe liquid being treated within the chamber 151, and more suitably, inthe illustrated embodiment, it is aligned coaxially with the chambersidewall 157. The horn assembly 133 has an outer surface 107 thattogether with an inner surface 167 of the sidewall 157 defines a flowpath within the interior space 153 of the chamber 151 along which thetwo or more phases (and the resulting-emulsion) flow past the hornwithin the chamber (this portion of the flow path being broadly referredto herein as the ultrasonic treatment zone). The horn assembly 133 hasan upper end defining a terminal end of the horn assembly (and thereforethe terminal end 113 of the waveguide assembly) and a longitudinallyopposite lower end 111. Although not shown, it is particularlypreferable that the waveguide assembly 203 also comprises a boostercoaxially aligned with and connected at an upper end thereof to thelower end 111 of the horn assembly 133. It is understood, however, thatthe waveguide assembly 203 may comprise only the horn assembly 133 andremain within the scope of this disclosure. It is also contemplated thatthe booster may be disposed entirely exterior of the chamber housing151, with the horn assembly 133 mounted on the chamber housing 151without departing from the scope of this disclosure.

The waveguide assembly 203, and more particularly the booster issuitably mounted on the chamber housing 151, e.g., on the tube 155defining the chamber sidewall 157, at the upper end thereof by amounting member (not shown) that is configured to vibrationally isolatethe waveguide assembly (which vibrates ultrasonically during operationthereof) from the treatment chamber housing. That is, the mountingmember inhibits the transfer of longitudinal and transverse mechanicalvibration of the waveguide assembly 203 to the chamber housing 151 whilemaintaining the desired transverse position of the waveguide assembly(and in particular the horn assembly 133) within the interior space 153of the chamber housing and allowing both longitudinal and transversedisplacement of the horn assembly within the chamber housing. Themounting member also at least in part (e.g., along with the booster,lower end of the horn assembly) closes the inlet end 125 of the chamber151. Examples of suitable mounting member configurations are illustratedand described in U.S. Pat. No. 6,676,003, the entire disclosure of whichis incorporated herein by reference to the extent it is consistentherewith.

In one particularly suitable embodiment the mounting member is of singlepiece construction. Even more suitably the mounting member may be formedintegrally with the booster (and more broadly with the waveguideassembly 203). However, it is understood that the mounting member may beconstructed separately from the waveguide assembly 203 and remain withinthe scope of this disclosure. It is also understood that one or morecomponents of the mounting member may be separately constructed andsuitably connected or otherwise assembled together.

In one suitable embodiment, the mounting member is further constructedto be generally rigid (e.g., resistant to static displacement underload) so as to hold the waveguide assembly 203 in proper alignmentwithin the interior space 153 of the chamber 151. For example, the rigidmounting member in one embodiment may be constructed of anon-elastomeric material, more suitably metal, and even more suitablythe same metal from which the booster (and more broadly the waveguideassembly 203) is constructed. The term “rigid” is not, however, intendedto mean that the mounting member is incapable of dynamic flexing and/orbending in response to ultrasonic vibration of the waveguide assembly203. In other embodiments, the rigid mounting member may be constructedof an elastomeric material that is sufficiently resistant to staticdisplacement under load but is otherwise capable of dynamic flexingand/or bending in response to ultrasonic vibration of the waveguideassembly 203.

A suitable ultrasonic drive system 131 including at least an exciter(not shown) and a power source (not shown) is disposed exterior of thechamber 151 and operatively connected to the booster (not shown) (andmore broadly to the waveguide assembly 203) to energize the waveguideassembly to mechanically vibrate ultrasonically. Examples of suitableultrasonic drive systems 131 include a Model 20A3000 system availablefrom Dukane Ultrasonics of St. Charles, Ill., and a Model 2000CS systemavailable from Herrmann Ultrasonics of Schaumberg, Ill.

In one embodiment, the drive system 131 is capable of operating thewaveguide assembly 203 at a frequency in the range of about 15 kHz toabout 100 kHz, more suitably in the range of about 15 kHz to about 60kHz, and even more suitably in the range of about 20 kHz to about 40kHz. Such ultrasonic drive systems 131 are well known to those skilledin the art and need not be further described herein.

In some embodiments, however not illustrated, the treatment chamber caninclude more than one waveguide assembly having at least two hornassemblies for ultrasonically treating and mixing the phases together toprepare the emulsion. As noted above, the treatment chamber comprises ahousing defining an interior space of the chamber through which thephases are delivered from an inlet end. The housing comprises anelongate tube defining, at least in part, a sidewall of the chamber. Aswith the embodiment including only one waveguide assembly as describedabove, the tube may have more than two inlet ports formed therein,through which at least two phases to be mixed within the chamber aredelivered to the interior space thereof, and at least one outlet portthrough which the emulsion exits the chamber.

In such an embodiment, two or more waveguide assemblies extendlongitudinally at least in part within the interior space of the chamberto ultrasonically energize and mix the phases (and resulting-emulsion)flowing through the interior space of the chamber. Each waveguideassembly separately includes an elongate horn assembly, each disposedentirely within the interior space of the housing intermediate the inletports and the outlet port for complete submersion within the phasesbeing mixed within the chamber. Each horn assembly can be independentlyconstructed as described more fully herein (including the horns, alongwith the plurality of agitating members and baffle assemblies).

Referring back to FIG. 1, the horn assembly 133 comprises an elongate,generally cylindrical horn 105 having an outer surface 107, and two ormore (i.e., a plurality of) agitating members 137 connected to the hornand extending at least in part transversely outward from the outersurface of the horn in longitudinally spaced relationship with eachother. The horn 105 is suitably sized to have a length equal to aboutone-half of the resonating wavelength (otherwise commonly referred to asone-half wavelength) of the horn. In one particular embodiment, the horn105 is suitably configured to resonate in the ultrasonic frequencyranges recited previously, and most suitably at 20 kHz. For example, thehorn 105 may be suitably constructed of a titanium alloy (e.g., Ti₆Al₄V)and sized to resonate at 20 kHz. The one-half wavelength horn 105operating at such frequencies thus has a length (corresponding to aone-half wavelength) in the range of about 4 inches to about 6 inches,more suitably in the range of about 4.5 inches to about 5.5 inches, evenmore suitably in the range of about 5.0 inches to about 5.5 inches, andmost suitably a length of about 5.25 inches (133.4 mm). It isunderstood, however, that the treatment chamber 151 may include a horn105 sized to have any increment of one-half wavelength without departingfrom the scope of this disclosure.

In one embodiment (not shown), the agitating members 137 comprise aseries of five washer-shaped rings that extend continuously about thecircumference of the horn in longitudinally spaced relationship witheach other and transversely outward from the outer surface of the horn.In this manner the vibrational displacement of each of the agitatingmembers relative to the horn is relatively uniform about thecircumference of the horn. It is understood, however, that the agitatingmembers need not each be continuous about the circumference of the horn.For example, the agitating members may instead be in the form of spokes,blades, fins or other discrete structural members that extendtransversely outward from the outer surface of the horn. For example, asillustrated in FIG. 1, one of the five agitating members is in a T-shape701. Specifically, the T-shaped agitating member 701 surrounds the nodalregion. It has been found that members in the T-shape, generate a strongradial (e.g., horizontal) acoustic wave that further increases thecavitation effect as described more fully herein.

By way of a dimensional example, the horn assembly 133 of theillustrated embodiment of FIG. 1 has a length of about 5.25 inches(133.4 mm), one of the rings 137 is suitably disposed adjacent theterminal end 113 of the horn 105 (and hence of the waveguide assembly203), and more suitably is longitudinally spaced approximately 0.063inches (1.6 mm) from the terminal end of the horn 105. In otherembodiments the uppermost ring may be disposed at the terminal end ofthe horn 105 and remain within the scope of this disclosure. The rings137 are each about 0.125 inches (3.2 mm) in thickness and arelongitudinally spaced from each other (between facing surfaces of therings) a distance of about 0.875 inches (22.2 mm).

It is understood that the number of agitating members 137 (e.g., therings in the illustrated embodiment) may be less than or more than fivewithout departing from the scope of this disclosure. It is alsounderstood that the longitudinal spacing between the agitating members137 may be other than as illustrated in FIG. 1 and described above(e.g., either closer or spaced further apart). Furthermore, while therings 137 illustrated in FIG. 1 are equally longitudinally spaced fromeach other, it is alternatively contemplated that where more than twoagitating members are present the spacing between longitudinallyconsecutive agitating members need not be uniform to remain within thescope of this disclosure.

In particular, the locations of the agitating members 137 are at leastin part a function of the intended vibratory displacement of theagitating members upon vibration of the horn assembly 133. For example,in the illustrated embodiment of FIG. 1, the horn assembly 133 has anodal region located generally longitudinally centrally of the horn 105(e.g., at the third ring). As used herein and more particularly shown inFIG. 1, the “nodal region” of the horn 105 refers to a longitudinalregion or segment of the horn member along which little (or no)longitudinal displacement occurs during ultrasonic vibration of the hornand transverse (e.g., radial in the illustrated embodiment) displacementof the horn is generally maximized. Transverse displacement of the hornassembly 133 suitably comprises transverse expansion of the horn but mayalso include transverse movement (e.g., bending) of the horn.

In the illustrated embodiment of FIG. 1, the configuration of theone-half wavelength horn 105 is such that the nodal region isparticularly defined by a nodal plane (i.e., a plane transverse to thehorn member at which no longitudinal displacement occurs whiletransverse displacement is generally maximized) is present. This planeis also sometimes referred to as a “nodal point”. Accordingly, agitatingmembers 137 (e.g., in the illustrated embodiment, the rings) that aredisposed longitudinally further from the nodal region of the horn 105will experience primarily longitudinal displacement while agitatingmembers that are longitudinally nearer to the nodal region willexperience an increased amount of transverse displacement and adecreased amount of longitudinal displacement relative to thelongitudinally distal agitating members.

It is understood that the horn 105 may be configured so that the nodalregion is other than centrally located longitudinally on the horn memberwithout departing from the scope of this disclosure. It is alsounderstood that one or more of the agitating members 137 may belongitudinally located on the horn so as to experience both longitudinaland transverse displacement relative to the horn upon ultrasonicvibration of the horn 105.

Still referring to FIG. 1, the agitating members 137 are sufficientlyconstructed (e.g., in material and/or dimension such as thickness andtransverse length, which is the distance that the agitating memberextends transversely outward from the outer surface 107 of the horn 105)to facilitate dynamic motion, and in particular dynamic flexing/bendingof the agitating members in response to the ultrasonic vibration of thehorn. In one particularly suitable embodiment, for a given ultrasonicfrequency at which the waveguide assembly 203 is to be operated in thetreatment chamber (otherwise referred to herein as the predeterminedfrequency of the waveguide assembly) and a particular liquid to betreated within the chamber 151, the agitating members 137 and horn 105are suitably constructed and arranged to operate the agitating membersin what is referred to herein as an ultrasonic cavitation mode at thepredetermined frequency.

As used herein, the ultrasonic cavitation mode of the agitating membersrefers to the vibrational displacement of the agitating memberssufficient to result in cavitation (i.e., the formation, growth, andimplosive collapse of bubbles in a liquid) of the emulsion beingprepared at the predetermined ultrasonic frequency. For example, whereat least one of the phases for the emulsion flowing within the chambercomprises an aqueous phase, and the ultrasonic frequency at which thewaveguide assembly 203 is to be operated (i.e., the predeterminedfrequency) is about 20 kHZ, one or more of the agitating members 137 aresuitably constructed to provide a vibrational displacement of at least1.75 mils (i.e., 0.00175 inches, or 0.044 mm) to establish a cavitationmode of the agitating members. Similarly, when at least one of thephases for the emulsion is a hydrophobic phase (e.g., oil), and theultrasonic frequency is about 20 kHz, one ore more of the agitatingmembers 137 are suitable constructed to provide a vibrationaldisplacement of at least 1.75 mils. To establish a cavitation mode ofthe agitating members.

It is understood that the waveguide assembly 203 may be configureddifferently (e.g., in material, size, etc.) to achieve a desiredcavitation mode associated with the particular emulsion to be prepare.For example, as the viscosity of the phases being mixed to prepare theemulsion changes, the cavitation mode of the agitating members may needto be changed.

In particularly suitable embodiments, the cavitation mode of theagitating members corresponds to a resonant mode of the agitatingmembers whereby vibrational displacement of the agitating members isamplified relative to the displacement of the horn. However, it isunderstood that cavitation may occur without the agitating membersoperating in their resonant mode, or even at a vibrational displacementthat is greater than the displacement of the horn, without departingfrom the scope of this disclosure.

In one suitable embodiment, a ratio of the transverse length of at leastone and, more suitably, all of the agitating members to the thickness ofthe agitating member is in the range of about 2:1 to about 6:1. Asanother example, the rings each extend transversely outward from theouter surface 107 of the horn 105 a length of about 0.5 inches (12.7 mm)and the thickness of each ring is about 0.125 inches (3.2 mm), so thatthe ratio of transverse length to thickness of each ring is about 4:1.It is understood, however that the thickness and/or the transverselength of the agitating members may be other than that of the rings asdescribed above without departing from the scope of this disclosure.Also, while the agitating members 137 (rings) may suitably each have thesame transverse length and thickness, it is understood that theagitating members may have different thicknesses and/or transverselengths.

In the above described embodiment, the transverse length of theagitating member also at least in part defines the size (and at least inpart the direction) of the flow path along which the phases or otherflowable components in the interior space of the chamber flows past thehorn. For example, the horn may have a radius of about 0.875 inches(22.2 mm) and the transverse length of each ring is, as discussed above,about 0.5 inches (12.7 mm). The radius of the inner surface of thehousing sidewall is approximately 1.75 inches (44.5 mm) so that thetransverse spacing between each ring and the inner surface of thehousing sidewall is about 0.375 inches (9.5 mm). It is contemplated thatthe spacing between the horn outer surface and the inner surface of thechamber sidewall and/or between the agitating members and the innersurface of the chamber sidewall may be greater or less than describedabove without departing from the scope of this disclosure.

In general, the horn 105 may be constructed of a metal having suitableacoustical and mechanical properties. Examples of suitable metals forconstruction of the horn 105 include, without limitation, aluminum,monel, titanium, stainless steel, and some alloy steels. It is alsocontemplated that all or part of the horn 105 may be coated with anothermetal such as silver, platinum, gold, palladium, lead dioxide, andcopper to mention a few. In one particularly suitable embodiment, theagitating members 137 are constructed of the same material as the horn105, and are more suitably formed integrally with the horn. In otherembodiments, one or more of the agitating members 137 may instead beformed separate from the horn 105 and connected thereto.

While the agitating members 137 (e.g., the rings) illustrated in FIG. 1are relatively flat, i.e., relatively rectangular in cross-section, itis understood that the rings may have a cross-section that is other thanrectangular without departing from the scope of this disclosure. Theterm “cross-section” is used in this instance to refer to across-section taken along one transverse direction (e.g., radially inthe illustrated embodiment) relative to the horn outer surface 107).Additionally, as seen of the first two and last two agitating members137 (e.g., the rings) illustrated in FIG. 1 are constructed only to havea transverse component, it is contemplated that one or more of theagitating members may have at least one longitudinal (e.g., axial)component to take advantage of transverse vibrational displacement ofthe horn (e.g., at the third agitating member as illustrated in FIG. 1)during ultrasonic vibration of the waveguide assembly 203.

As best illustrated in FIG. 1, the terminal end 113 of the waveguideassembly (e.g., of the horn 105 in the illustrated embodiment) issuitably spaced longitudinally from the outlet port 165 at the outletend 127 in FIG. 1 to define what is referred to herein as a buffer zone(i.e., the portion of the interior space 153 of the chamber housing 151longitudinally beyond the terminal end 113 of the waveguide assembly203) to allow more uniform mixing of components as the phases (andresulting-emulsion) flow downstream of the terminal end 112 to theoutlet end 127 of the chamber 151. For example, in one suitableembodiment, the buffer zone has a void volume (i.e., the volume of thatportion of the open space 153 within the chamber housing 151 within thebuffer zone) in which the ratio of this buffer zone void volume to thevoid volume of the remainder of the chamber housing interior spaceupstream of the terminal end of the waveguide assembly is suitably inthe range of from about 0.01:1 to about 5.0:1, and more suitably about1:1.

Providing the illustrated buffer zone is particularly suitable where thechamber 151 is used for mixing phases together to form an emulsion asthe longitudinal spacing between the terminal end 113 of the waveguideassembly 203 and the outlet port 165 of the chamber 151 providessufficient space for the agitated flow of the mixed emulsion togenerally settle prior to the emulsion exiting the chamber via theoutlet port 127. This is particularly useful where, as in theillustrated embodiment, one of the agitating members 137 is disposed ator adjacent the terminal end of the horn 113. While such an arrangementleads to beneficial back-mixing of the emulsion as it flows past theterminal end of the horn 113, it is desirable that this agitated flowsettle out at least in part before exiting the chamber. It isunderstood, though, that the terminal end 113 of the horn 105 may benearer to the outlet end 127 than is illustrated in FIG. 1, and may besubstantially adjacent to the outlet port 165 so as to generally omitthe buffer zone, without departing from the scope of this disclosure.

Additionally, a baffle assembly, generally indicated at 245 is disposedwithin the interior space 153 of the chamber housing 151, and inparticular generally transversely adjacent the inner surface 167 of thesidewall 157 and in generally transversely opposed relationship with thehorn 105. In one suitable embodiment, the baffle assembly 245 comprisesone or more baffle members 247 disposed adjacent the inner surface 167of the housing sidewall 157 and extending at least in part transverselyinward from the inner surface of the sidewall 167 toward the horn 105.More suitably, the one or more baffle members 247 extend transverselyinward from the housing sidewall inner surface 167 to a positionlongitudinally intersticed with the agitating members 137 that extendoutward from the outer surface 107 of the horn 105. The term“longitudinally intersticed” is used herein to mean that a longitudinalline drawn parallel to the longitudinal axis of the horn 105 passesthrough both the agitating members 137 and the baffle members 247. Asone example, in the illustrated embodiment, the baffle assembly 245comprises four, generally annular baffle members 247 (i.e., extendingcontinuously about the horn 105) longitudinally intersticed with thefive agitating members 237.

As a more particular example, the four annular baffle members 247illustrated in FIG. 1 are of the same thickness as the agitating members137 in our previous dimensional example (i.e., 0.125 inches (3.2 mm))and are spaced longitudinally from each other (e.g., between opposedfaces of consecutive baffle members) equal to the longitudinal spacingbetween the rings (i.e., 0.875 inches (22.2 mm)). Each of the annularbaffle members 247 has a transverse length (e.g., inward of the innersurface 167 of the housing sidewall 157) of about 0.5 inches (12.7 mm)so that the innermost edges of the baffle members extend transverselyinward beyond the outermost edges of the agitating members 137 (e.g.,the rings). It is understood, however, that the baffle members 247 neednot extend transversely inward beyond the outermost edges of theagitating members 137 of the horn 105 to remain within the scope of thisdisclosure.

It will be appreciated that the baffle members 247 thus extend into theflow path of the phases (and resulting-emulsion) that flow within theinterior space 153 of the chamber 151 past the horn 105 (e.g., withinthe ultrasonic treatment zone). As such, the baffle members 247 inhibitthe phases from flowing along the inner surface 167 of the chambersidewall 157 past the horn 105, and more suitably the baffle membersfacilitate the flow of the phases transversely inward toward the hornfor flowing over the agitating members of the horn to thereby facilitateultrasonic energization (i.e., agitation) of the phases to initiatemixing of the phases to form an emulsion.

In one embodiment, to inhibit gas bubbles against stagnating orotherwise building up along the inner surface 167 of the sidewall 157and across the face on the underside of each baffle member 247, e.g., asa result of agitation of the phases within the chamber, a series ofnotches (broadly openings) may be formed in the outer edge of each ofthe baffle members (not shown) to facilitate the flow of gas (e.g., gasbubbles) between the outer edges of the baffle members and the innersurface of the chamber sidewall. For example, in one particularlypreferred embodiment, four such notches are formed in the outer edge ofeach of the baffle members in equally spaced relationship with eachother. It is understood that openings may be formed in the bafflemembers other than at the outer edges where the baffle members abut thehousing, and remain within the scope of this disclosure. It is alsounderstood, that these notches may number more or less than four, asdiscussed above, and may even be completely omitted.

It is further contemplated that the baffle members 247 need not beannular or otherwise extend continuously about the horn 105. Forexample, the baffle members 247 may extend discontinuously about thehorn 105, such as in the form of spokes, bumps, segments or otherdiscrete structural formations that extend transversely inward fromadjacent the inner surface 167 of the housing sidewall 157. The term“continuously” in reference to the baffle members 247 extendingcontinuously about the horn does not exclude a baffle member as beingtwo or more arcuate segments arranged in end-to-end abuttingrelationship, i.e., as long as no significant gap is formed between suchsegments. Suitable baffle member configurations are disclosed in U.S.application Ser. No. 11/530,311 (filed Sep. 8, 2006), which is herebyincorporated by reference to the extent it is consistent herewith.

Also, while the baffle members 247 illustrated in FIG. 1 are eachgenerally flat, e.g., having a generally thin rectangular cross-section,it is contemplated that one or more of the baffle members may each beother than generally flat or rectangular in cross-section to furtherfacilitate the flow of bubbles along the interior space 153 of thechamber 151. The term “cross-section” is used in this instance to referto a cross-section taken along one transverse direction (e.g., radiallyin the illustrated embodiment, relative to the horn outer surface 107).

As described above, in some embodiments, the waveguide assembly may beinverted within the chamber. Specifically, as shown in FIG. 2, thewaveguide assembly 303 is mounted to the chamber housing 251 at theoutlet end 227 and extends longitudinally downward within the interiorspace 253 of the chamber housing 251. The first and second phases (notshown) enter the chamber 251 through inlet ports 228 and 229 and travellongitudinally upward towards the terminal end of the horn 213 (and, asillustrated, the terminal end of the waveguide assembly) where thephases are ultrasonically energized and mixed to form an emulsion. Oncemixed, the emulsion travels to the outlet end 227 of the chamber 251 andexits the chamber 251 through the outlet port 265.

In one embodiment, although not illustrated, the ultrasonic mixingsystem may further comprise a filter assembly disposed at the outlet endof the treatment chamber. Many emulsions, when initially prepared, cancontain one or more components within the various phases that attractone another and can clump together in large balls. Furthermore, manytimes, particles within the prepared emulsions can settle out over timeand attract one another to form large balls; referred to asreagglomeration. As such, the filter assembly can filter out the largeballs of particles that form within the emulsions prior to the emulsionbeing delivered to an end-product for consumer use. Specifically, thefilter assembly is constructed to filter out particles sized greaterthan about 0.2 microns.

Specifically, in one particularly preferred embodiment, the filterassembly covers the inner surface of the outlet port. The filterassembly includes a filter having a pore size of from about 0.5 micronto about 20 microns. More suitably, the filter assembly includes afilter having a pore size of from about 1 micron to about 5 microns, andeven more suitably, about 2 microns. The number and pour size of filtersfor use in the filter assembly will typically depend on the formulation(and its components) to be mixed within the treatment chamber.

A degasser may also be included in the ultrasonic mixing system. Forexample, once the prepared emulsion exits the treatment chamber, theemulsion flows into a degasser in which excess gas bubbles are removedfrom the emulsion prior to the emulsion being used into a consumerend-products, such as a cosmetic formulation.

One particularly preferred degasser is a continuous flow gas-liquidcyclone separator, such as commercially available from NATCO (Houston,Tex.). It should be understood by a skilled artisan, however, that anyother system that separates gas from an emulsion by centrifugal actioncan suitably be used without departing from the present disclosure.

In operation according to one embodiment of the ultrasonic mixing systemof the present disclosure, the mixing system (more specifically, thetreatment chamber) is used to mix two or more phases together to form anemulsion. Specifically, at least a first phase is delivered (e.g., bythe pumps described above) via conduits to a first inlet port formed inthe treatment chamber housing and a second phase is delivered (e.g., bythe pumps described above) via separate conduits to a second inlet portformed in the treatment chamber housing. The phases can be any suitablephases for forming emulsions known in the art. Suitable phases caninclude, for example, an oil phase, a water phase, a silicone phase, aglycol phase, and combinations thereof. When mixed in variouscombinations, the phases form emulsions such as oil-in-water emulsions,water-in-oil emulsions, water-in-oil-in-water emulsions,oil-in-water-in-oil emulsions, water-in-silicone emulsions,water-in-silicone-in-water emulsions, glycol-in-silicone emulsion, highinternal phase emulsions, hydrogels, and the like. High internal phaseemulsions are well known in the art and typically refer to emulsionshaving from about 70% (by total weight emulsion) to about 80% (by totalweight emulsion) of an oil phase. Furthermore, as known by one skilledin the art, “hydrogel” typically refers to a hydrophilic base that isthickened with rheology modifiers and or thickeners to form a gel. Forexample a hydrogel can be formed with a base consisting of water that isthickened with a carbomer that has been neutralized with a base.

Without being limited, the present disclosure will describe a method ofpreparing an oil-in-water emulsion using the ultrasonic mixing system asdescribed herein. It should be recognized that while described in termsof preparing an oil-in-water emulsion, any of the above-listed emulsionsmay be prepared using the general process described without departingfrom the scope of the present disclosure. Generally, the method forpreparing the oil-in-water emulsion includes: delivering a first phase(i.e., an oil phase) via a first inlet port into the interior space ofthe treatment chamber housing and a second phase (i.e., a water phase)via a second inlet port into the interior space of the treatment chamberhousing. Typically, as described more fully above, the first and secondinlet ports are disposed in parallel along the sidewall of the treatmentchamber housing. In an alternative embodiment, the first and secondinlet ports are disposed on opposite sidewalls of the treatment chamberhousing. While described herein as having two inlet ports, it should beunderstood by one skilled in the art that more than two inlet ports canbe used to deliver the various phases to be mixed without departing fromthe scope of the present disclosure.

Particularly preferred oil-in-water emulsions can be prepared with anoil phase including from about 0.1% (by total weight of oil phase) toabout 99% (by total weight of oil phase) oil. More suitably, the oilphase includes from about 1% (by total weight of oil phase) to about 80%(by total weight of oil phase) oil and, even more suitably, from about5% (by total weight of oil phase) to about 50% (by total weight of oilphase) oil. The oils can be natural oil, synthetic oils, andcombinations thereof.

The term “natural oil” is intended to include oils, essential oils, andcombinations thereof. Suitable oils include Apricot Kernel Oil, AvocadoOil, Babassu Oil, Borage Seed Oil, Camellia Oil, Canola Oil, Carrot Oil,Cashew Nut Oil, Castor Oil, Cherry Pit Oil, Chia Oil, Coconut Oil, CodLiver Oil, Corn Germ Oil, Corn Oil, Cottonseed Oil, Egg Oil, EpoxidizedSoybean Oil, Evening Primrose Oil, Grape Seed Oil, Hazelnut Oil, HybridSafflower Oil, Hybrid Sunflower Seed Oil, Hydrogenated Castor Oil,Hydrogenated Castor Oil Laurate, Hydrogenated Coconut Oil, HydrogenatedCottonseed Oil, Hydrogenated Fish Oil, Hydrogenated Menhaden Oil,Hydrogenated Mink Oil, Hydrogenated Orange Roughy Oil, Hydrogenated PalmKernel Oil, Hydrogenated Palm Oil, Hydrogenated Peanut Oil, HydrogenatedShark Liver Oil, Hydrogenated Soybean Oil, Hydrogenated Vegetable Oil,Lanolin and Lanolin Derivatives, Lesquerella Oil, Linseed Oil, MacadamiaNut Oil, Maleated Soybean Oil, Meadowfoam Seed Oil, Menhaden Oil, MinkOil, Moringa Oil, Mortierella Oil, Neatsfoot Oil, Olive Husk Oil, OliveOil, Orange Roughy Oil, Palm Kernel Oil, Palm Oil, Peach Kernel Oil,Peanut Oil, Pengawar Djambi Oil, Pistachio Nut Oil, Rapeseed Oil, RiceBran Oil, Safflower Oil, Sesame Oil, Shark Liver Oil, Soybean Oil,Sunflower Seed Oil, Sweet Almond Oil, Tall Oil, Vegetable Oil, WalnutOil, Wheat Bran Lipids, Wheat Germ Oil, Zadoary Oil, oil extracts ofvarious other botanicals, and other vegetable or partially hydrogenatedvegetable oils, and the like, as well as mixtures thereof.

Suitable essential oils include Anise Oil, Balm Mint Oil, Basil Oil, BeeBalm Oil, Bergamot Oil, Birch Oil, Bitter Almond Oil, Bitter Orange Oil,Calendula Oil, California Nutmeg Oil, Caraway Oil, Cardamom Oil,Chamomile Oil, Cinnamon Oil, Clary Oil, Cloveleaf Oil, Clove Oil,Coriander Oil, Cypress Oil, Eucalyptus Oil, Fennel Oil, Gardenia Oil,Geranium Oil, Ginger Oil, Grapefruit Oil, Hops Oil, Hyptis Oil, IndigoBush Oil, Jasmine Oil, Juniper Oil, Kiwi Oil, Laurel Oil, Lavender Oil,Lemongrass Oil, Lemon Oil, Linden Oil, Lovage Oil, Mandarin Orange Oil,Matricaria Oil, Musk Rose Oil, Nutmeg Oil, Olibanum, Orange Flower Oil,Orange Oil, Patchouli Oil, Pennyroyal Oil, Peppermint Oil, Pine Oil,Pine Tar Oil, Rose Hips Oil, Rosemary Oil, Rose Oil, Rue Oil, Sage Oil,Sambucus Oil, Sandalwood Oil, Sassafras Oil, Silver Fir Oil, SpearmintOil, Sweet Marjoram Oil, Sweet Violet Oil, Tar Oil, Tea Tree Oil, ThymeOil, Wild Mint Oil, Yarrow Oil, Ylang Ylang Oil, and the like, as wellas mixtures thereof.

Some preferred natural oils include, but are not limited to Avocado Oil,Apricot Oil, Babassu Oil, Borage Oil, Camellia oil, Canola oil, CastorOil, Coconut oil, Corn Oil, Cottonseed Oil, Evening Primrose Oil,Hydrogenated Cottonseed Oil, Hydrogenated Palm Kernel Oil, MaleatedSoybean Oil, Meadowfoam Oil, Palm Kernel Oil, Phospholipids, RapeseedOil, Rose Hip Oil, Sunflower Oil, Soybean Oil, and the like, as well asmixtures thereof.

The term “synthetic oil” is intended to include synthetic oils, esters,silicones, other emollients, and combinations thereof. Examples ofsuitable synthetic oils include petrolatum and petrolatum based oils,mineral oils, mineral jelly, isoparaffins, polydimethylsiloxanes such asmethicone, cyclomethicone, dimethicone, dimethiconol, trimethicone,alkyl dimethicones, alkyl methicones, alkyldimethicone copolyols,organo-siloxanes (i.e., where the organic functionality can be selectedfrom alkyl, phenyl, amine, polyethylene glycol, amine-glycol, alkylaryl,carboxal, and the like), silicones such as silicone elastomer, phenylsilicones, alkyl trimethylsilanes, dimethicone crosspolymers,cyclomethicone, gums, resins, fatty acid esters (esters of C₆-C₂₈ fattyacids and C₆-C₂₈ fatty alcohols), glyceryl esters and derivatives, fattyacid ester ethoxylates, alkyl ethoxylates, C₁₂-C₂₈ fatty alcohols,C₁₂-C₂₈ fatty acids, C₁₂-C₂₈ fatty alcohol ethers, propylene glycolesters and derivatives, alkoxylated carboxylic acids, alkoxylatedalcohols, fatty alcohols, Guerbet alcohols, Guerbet Acids, GuerbetEsters, and other cosmetically acceptable emollients.

Specific examples of suitable esters may include, but are not limitedto, cetyl palmitate, stearyl palmitate, cetyl stearate, isopropyllaurate, isopropyl myristate, isopropyl palmitate, and combinationsthereof.

In addition to the oil, the oil phase of the oil-in-water emulsion mayfurther include one or more surfactants and/or antioxidants. It shouldbe recognized, however, that the oil phase may not contain asurfactant/antioxidant without departing from the scope of the presentdisclosure. Furthermore, due to the cavitation produced with theultrasonic treatment system, when surfactants are used, less surfactantneeds to be added. While described herein in the oil phase, it should berecognized by one skilled in the art, that one or more surfactants canbe added to the water phase in addition to or as an alternative to beingadded to the oil phase without departing from the scope of the presentdisclosure.

As noted above, emulsions are typically prepared using surfactants asthe surfactants may contribute to the overall cleansing, emulsificationproperties of the emulsion. Additionally, the surfaces may be utilizedto provide emulsions that are mild to the skin and have a low likelihoodof stripping essential oils from the user, thereby creating irritation.Preferably, the oil phase contains from about 0.1% (by total weight oilphase) to about 20% (by total weight oil phase) surfactant. Moresuitably, the oil phase contains from about 1% (by total weight oilphase) to about 15% (by total weight oil phase) surfactant and, evenmore suitably, from about 2% (by total weight oil phase) to about 10%(by total weight oil phase) surfactant.

Suitable surfactants can be nonionic surfactants, anionic surfactants,cationic surfactants, amphoteric surfactants, and combinations thereof.Suitable anionic surfactants include, for example, alkyl sulfates, alkylether sulfates, alkyl aryl sulfonates, alpha-olefin sulfonates, alkalimetal or ammonium salts of alkyl sulfates, alkali metal or ammoniumsalts of alkyl ether sulfates, alkyl phosphates, silicone phosphates,alkyl glyceryl sulfonates, alkyl sulfosuccinates, alkyl taurates, acyltaurates, alkyl sarcosinates, acyl sarcosinates, sulfoacetates, alkylphosphate esters, mono alkyl succinates, monoalkyl maleates,sulphoacetates, acyl isethionates, alkyl carboxylates, phosphate esters,sulphosuccinates (e.g., sodium dioctylsulphosuccinate), and combinationsthereof. Specific examples of anionic surfactants include sodium laurylsulphate, sodium lauryl ether sulphate, ammonium lauryl sulphosuccinate,ammonium lauryl sulphate, ammonium lauryl ether sulphate, sodiumdodecylbenzene sulphonate, triethanolamine dodecylbenzene sulphonate,sodium cocoyl isethionate, sodium lauroyl isethionate, sodium N-laurylsarcosinate, and combinations thereof.

Suitable cationic surfactants include, for example, alkyl ammoniumsalts, polymeric ammonium salts, alkyl pyridinium salts, aryl ammoniumsalts, alkyl aryl ammonium salts, silicone quaternary ammoniumcompounds, and combinations thereof. Specific examples of cationicsurfactants include behenyltrimonium chloride, stearlkonium chloride,distearalkonium chloride, chlorohexidine diglutamate, polyhexamethylenebiguanide (PHMB), cetyl pyridinium chloride, benzammonium chloride,benzalkonium chloride, and combinations thereof.

Suitable amphoteric surfactants include, for example, betaines,alkylamido betaines, sulfobetaines, N-alkyl betaines, sultaines,amphoacetates, amophodiacetates, imidazoline carboxylates, sarcosinates,acylamphoglycinates, such as cocamphocarboxyglycinates andacylamphopropionates, and combinations thereof. Specific examples ofamphoteric surfactants include cocamidopropyl betaine, lauramidopropylbetaine, meadowfoamamidopropyl betaine, sodium cocoyl sarcosinate,sodium cocamphoacetate, disodium cocoamphodiacetate, ammonium cocoylsarcosinate, sodium cocoamphopropionate, and combinations thereof.

Suitable zwitterionic surfactants include, for example, alkyl amineoxides, silicone amine oxides, and combinations thereof. Specificexamples of suitable zwitterionic surfactants include, for example,4-[N,N-di(2-hydroxyethyl)-N-octadecylammonio]-butane-1-carboxylate,S-[S-3-hydroxypropyl-S-hexadecylsulfonio]-3-hydroxypentane-1-sulfate,3-[P,P-diethyl-P-3,6,9-trioxatetradexopcylphosphonio]-2-hydroxypropane-1-phosphate,3-[N,N-dipropyl-N-3-dodecoxy-2-hydroxypropylammonio]-propane-1-phosphonate,3-(N,N-dimethyl-N-hexadecylammonio)propane-1-sulfonate,3-(N,N-dimethyl-N-hexadecylammonio)-2-hydroxypropane-1-sulfonate,4-[N,N-di(2-hydroxyethyl)-N-(2-hydroxydodecyl)ammonio]-butane-1-carboxylate,3-[S-ethyl-S-(3-dodecoxy-2-hydroxypropyl)sulfonio]-propane-1-phosphate,3-[P,P-dimethyl-P-dodecylphosphonio]-propane-1-phosphonate,5-[N,N-di(3-hydroxypropyl)-N-hexadecylammonio]-2-hydroxy-pentane-1-sulfate,and combinations thereof.

Suitable non-ionic surfactants include, for example, mono- anddi-alkanolamides such as, for example, cocamide MEA and cocamide DEA,amine oxides, alkyl polyglucosides, ethoxylated silicones, ethoxylatedalcohols, ethoxylated carboxylic acids, ethoxylated amines, ethoxylatedamides, ethoxylated alkylolamides, ethoxylated alkylphenols, ethoxylatedglyceryl esters, ethoxylated sorbitan esters, ethoxylated phosphateesters, glycol stearate, glyceryl stearate, and combinations thereof.

Additionally, the oil phase may include one or more antioxidants.Suitable antioxidants include, for example, BHT, BHA, Vitamin E,ceramide or ceramide derivatives, such as glucosylceramides,acylceramide, bovine ceramides, sphingolipid E, and combinationsthereof.

Additionally, the oil-in-water emulsion includes a water phase havingfrom about 0.1% (by total weight of water phase) to about 99% (by totalweight of water phase) water, and a balance of components includinghumectants, chelating agents, and preservatives. Suitable humectants mayinclude glycerin, glycerin derivatives, sodium hyaluronate, betaine,amino acids, glycosaminoglycans, honey, sorbitol, glycols, polyols,sugars, hydrogenated starch hydrolysates, salts of PCA, lactic acid,lactates, and urea. A particularly preferred humectant is glycerin.

Chelating agents may act to enhance preservative efficacy, and bindmetals that could discolor the emulsion or hinder emulsion stability.Suitable chelating agents include, for example, disodium ethylenediaminetetraacetic acid (EDTA), commercially available from the Dow ChemicalCompany under the name VERSENE Na₂.

Additionally, as noted above, the water phase may include one or morepreservatives. Suitable preservatives include, for example, the loweralkyl esters of para-hydroxybenzoates such as methylparaben,propylparaben, isobutylparaben, and mixtures thereof, benzyl alcohol,DMDM Hydantoin, and benzoic acid.

In one embodiment, the phases are mixed with one or more thickeners toprovide a thicker emulsion. Specifically, when the emulsion is ahydrogel, basic pH adjusters, such as sodium hydroxide, are preferablyused to thicken the emulsion.

A variety of thickeners may be used in the phases described herein. Inone embodiment, the thickener may be a cellulosic thickener or gum.Examples of suitable cellulosic or gum thickeners include xanthan gum,agar, alginates, carrageenan, furcellaran, guar, cationic guar, gumarabic, gum tragacanth, karaya gum, locust bean gum, dextran, starch,modified starches, gellan gum, carboxymethylcellulose,hydroxypropylcellulose, hydroyethylcellulose, propylene glycol alginate,hydroxypropyl guar, amylopectin, cellulose gum, chitosan, modifiedchitosan, hydroxypropyl methylcellulose, microcrystalline cellulose,silica, fumed silica, colloidal silica, dehydroxanthan gum, non-acrylicbased carbomers, and combinations thereof.

Alternately or in addition, the thickener may be an acrylic basedpolymer. Non-limiting examples of suitable acrylic based polymerthickeners include acrylates/C₁₀-C₃₀ alkyl acrylate crosspolymers,certain carbomers, acrylates copolymers, aminoacrylates copolymers, andcombinations thereof. Examples of commercially available acrylic basedpolymer thickeners include Structure® Plus (National Starch & Chemical,Bridgewater, N.J.), which is an acrylates/aminoacrylates/C₁₀₋₃₀ alkylPEG-20 itaconate copolymer, Carbopol® Aqua SF-1 Polymer (Noveon,Cleveland Ohio), which is an acrylates copolymer, Pemulen® TR-1 and TR-2and Carbopol® ETD 2020 (available from Noveon), which areacrylates/C10-30 alkyl acrylates crosspolymers, and the Carbopol® Ultrezseries of polymers (available from Noveon), which are carbomers.

In one embodiment, such when using a hydrogel as described above, thephase (e.g., hydrogel) may be formulated using an acid-sensitivethickener and/or a base-sensitive thickener. As the names suggest,acid-sensitive thickeners are activated (i.e., swell or “thicken”) uponcontact with an acidic agent, while base-sensitive thickeners areactivated upon contact with an alkaline agent. An acid- orbase-sensitive thickener may be combined with other phase componentsprior to activation, and activated by contact with an acidic or alkalineagent after the acid- or base-sensitive thickener is dispersedthroughout the phase.

Examples of suitable acid-sensitive thickeners for use in the phasesinclude the Structure® Plus (National Starch & Chemical, Bridgewater,N.J.) thickener, described above. The acid-sensitive thickeners may beactivated by contact with any of a wide range of acidic agentsincluding, for example, glycolic acid, lactic acid, phosphoric acid,citric acid, other organic acids, and similar acidic agents. Acidsensitive thickeners are generally activated over a pH range of fromabout 3 to about 9, and more typically over a pH range of from about 3to about 7. The Structure® Plus thickener is typically activated over apH range of from about 3 to about 9.

Examples of suitable base-sensitive thickeners include the Carbopol®Aqua SF-1 Polymer (Noveon, Cleveland Ohio) thickener, described above,as well as the Pemulen® TR-1 and TR-2 thickeners (available fromNoveon), the Carbopol® ETD 2020 thickeners (available from Noveon), andthe Carbopol® Ultrez series of thickeners (available from Noveon), alldescribed above, and other carbomers and starches, and combinationsthereof. The base-sensitive thickeners may be activated by contact withany of a wide range of alkaline agents including, for example, variousmetal hydroxides and amines, and other similar alkaline agents.Non-limiting examples of suitable metal hydroxides include potassiumhydroxide and sodium hydroxide. Non-limiting examples of suitable aminesinclude triethanolamine, diethanolamine, monoethanolamine, tromethamine,aminomethylpropanol, triisopropanolamine, diisopropanolamine,tetrahydroxypropylethylenediamine, and PEG-15 cocoamine. Base sensitivethickeners are generally activated over a pH range of from about 5 toabout 11, and more typically over a pH range of from about 6 to about11.

Although described above as using a thickener with a hydrogel, it shouldbe recognized by one skilled in the art that the above thickeners can beused with any of the phases described herein for preparing an emulsion.

In certain embodiments, one or more of the phases may include two ormore different types of thickeners. For instance, the phases may includeany combination of cellulosic thickeners, gum thickeners, acid-sensitivethickeners, base-sensitive thickeners, and/or acrylic based polymerthickeners.

While as disclosed herein in terms of mixing phases to prepare theemulsions, it should it be recognized that one emulsion, prepared usingany method known in the art, can be mixed with one or more additionalphases to make a second emulsion using the ultrasonic mixing system andthe methods described herein without departing from the scope of thepresent disclosure. For example, in one embodiment, awater-in-oil-in-water emulsion is prepared and is delivered via a firstinlet port into the interior space of the treatment chamber housing anda separate phase (i.e., a water phase, as described above) is deliveredvia a second inlet port into the interior space of the treatment chamberhousing. The ultrasonic mixing system (and, more particularly, thewaveguide assembly), operating in the predetermined frequency asdescribed above, mixes the water-in-oil emulsion with the water phase toproduce a water-in-oil-in-water emulsion.

In one embodiment, one or more the phases are heated prior to beingdelivered to the treatment chamber. Specifically, with some emulsions,while some or all of the individual phases have a relatively lowviscosity (i.e., a viscosity below 100 cps), the other phases or theresulting-emulsion that is prepared from the phases has a high viscosity(i.e., a viscosity greater than 100 cps), which can result in clumpingof the emulsion and clogging of the outlet port of the treatmentchamber. For example, many water-in-oil emulsions can suffer fromclumping during mixing. In these types of emulsions, the water and/oroil phases are typically heated to a temperature of approximately 40° C.or higher prior to being mixed. Suitably, one or more of the phases canbe heated to a temperature of from about 70° C. to about 100° C. priorto being delivered to the treatment chamber via the inlet ports.

Typically, the oil phase and water phase are delivered to the treatmentchamber at a flow rate of from about 1 gram per minute to about 100,000grams per minute. In one embodiment, the oil phase and water phase havedifferent flow rates. By way of example, in one particular embodiment,the oil phase can be delivered via the first inlet port at a flow rateof from about 1 gram per minute to about 10,000 grams per minute, andthe water phase can be delivered via the second inlet port at a flowrate of from about 1 gram per minute to about 10,000 grams per minute.In an alternative embodiment, the oil phase and water phase aredelivered into the interior of the treatment chamber at equal flowrates.

In accordance with the above embodiment, as the water and oil phasescontinue to flow upward within the chamber, the waveguide assembly, andmore particularly the horn assembly, is driven by the drive system tovibrate at a predetermined ultrasonic frequency to mix the phases,thereby preparing the emulsion. Specifically, in response to ultrasonicexcitation of the horn, the agitating members that extend outward fromthe outer surface of the horn dynamically flex/bend relative to thehorn, or displace transversely (depending on the longitudinal positionof the agitating member relative to the nodal region of the horn).

The phases continuously flow longitudinally along the flow path betweenthe horn assembly and the inner surface of the housing sidewall so thatthe ultrasonic vibration and the dynamic motion of the agitating memberscause cavitation in the phases to further facilitate agitation. Thebaffle members disrupt the longitudinal flow of liquid along the innersurface of the housing sidewall and repeatedly direct the flowtransversely inward to flow over the vibrating agitating members.

As the mixed emulsion flows longitudinally downstream past the terminalend of the waveguide assembly, an initial back mixing of the emulsionalso occurs as a result of the dynamic motion of the agitating member ator adjacent the terminal end of the horn. Further downstream flow of theemulsion results in the agitated liquid providing a more uniform mixtureof the phases prior to exiting the treatment chamber via the outletport.

The present disclosure is illustrated by the following examples whichare merely for the purpose of illustration and are not to be regarded aslimiting the scope of the disclosure or manner in which it may bepracticed.

EXAMPLE 1

In this Example, the ability of the ultrasonic mixing system of thepresent disclosure to mix an oil phase and aqueous liquid phase to forman oil-in-water type emulsion was analyzed. Specifically, the ability ofthe ultrasonic mixing system to mix dispersions of mineral oil into adiluted wet wipes solution was analyzed.

The diluted wet wipe solution included 4.153% (by weight) KIMSPEC AVE®(commercially available from Rhodia, Inc., Cranbury, N.J.) and 95.848%(by weight) purified water. The solution was prepared by mixing theKIMSPEC AVE® into water using a propeller mixer, available from IKA®EUROSTAR, IKA Works Co., Wilmington, N.C.), rotating at a speed of about540 revolutions per minute (rpm). Four separate samples of the dilutedwet wipe solution were prepared. The solution for each sample wasdelivered to a first inlet port of the ultrasonic mixing system of FIG.1.

Additionally, a flow of mineral oil, available as PenrecoO Drakeol® LTmineral oil N.F. from Penreco Co., The Woodlands, Tex.) was delivered toa second inlet port of the ultrasonic mixing system shown in FIG. 1. Theweight ratio of mineral oil to wet wipe solution was 1:199. Threedifferent flow rates of the emulsion samples were used for samples A, B,and C (4000 grams per minute, 2000 grams per minute, and 1000 grams perminute, respectively). Additionally, one wet wipe solution (Sample D)was produced by adding 1% (by total weight solution) of surfactant,commercially available as Solubilisant LRI from LCW, South Plainfield,N.J.), so the weight ratio of oil to surfactant to wet wipe solution was1:2:197. The flow rate of Sample D was 1000 grams per minute.

The ultrasonic mixing system was then ultrasonically activated using theultrasonic drive system at a frequency of 20 kHz. After mixing in thetreatment chamber, the wet wipe solutions (now having the mineral oilincorporated therein) exited the treatment chamber via the outlet port.The physical appearances of the emulsions observed are summarized inTable 1. The size and distribution of oil droplets within the emulsionsso prepared were analyzed using the Laser Light Scattering Method byMicromeritics Analytical Services (Norcross, Ga.) after thirteen days ofthe experiment. The data on mean particle size and size distribution ofthe mineral oil droplets in the wet wipe solutions are shown in Table 2.

TABLE 1 Flow Rate of Mineral Oil Wet Wipe into Mixing Mixing VisualAppearance of Solution System Time Wet Wipe Solution Sample (g/min)(minutes) Containing Mineral Oil A 20 0.5 Translucent, milk-like, novisible droplets B 10 1 Milk-like; less transparent than A; no visibledroplets C 5 2 Milk-like; not transparent; no visible droplets D 5 2Milk-like; not transparent; no visible droplets

TABLE 2 Mean Wet Wipe particulate Diameter Solution diameter Diameter50% finer Diameter Sample (μm) 90% finer (Median) 10% finer A 1.8623.368 1.381 0.576 B 1.110 2.266 0.655 0.190 C 0.654 1.375 0.379 0.142 D0.767 1.536 0.510 0.166

As shown in Table 2, the wet wipe solutions C and D, which were mixed inthe ultrasonic mixing system for two minutes, had smaller particle sizesof mineral oil droplets, showing a better dispersion of mineral oilwithin the aqueous wet wipe solution.

Additionally, after 40 days, the appearances of the wet wipe solutionsamples were analyzed visually. All wet wipe solutions contained a thincreamy layer on top, but the layer was miscible with the remainingportion of the sample with slight agitation.

EXAMPLE 2

In this Example, the ultrasonic mixing system of the present disclosurewas used to emulsify an oil phase into a water phase to produce anoil-in-water emulsion. The ability of the ultrasonic mixing system toprepare a stable oil-in-water emulsion was analyzed and compared to anoil-in-water emulsion prepared using a traditional cold mix procedure asdescribed above.

Three oil-in-water emulsions were prepared. Specifically, theoil-in-water emulsions were prepared by mixing 1 part mineral oil(available as PenrecoO DrakeolO LT mineral oil N.F. from Penreco Co.,The Woodlands, Tex.)) to 199 parts water for a mixing period ofapproximately 2 minutes. The first emulsion sample (Sample 1) wasprepared using a propeller mixer (IKA® EUROSTAR, IKA Works, Co.,Wilmington, N.C.) and using the standard cold mix batch procedure.

The other two oil-in-water emulsions (Samples 2 and 3) were prepared inthe ultrasonic mixing system of FIG. 1. Specifically, to produce theoil-in-water emulsion of Sample 2 with the ultrasonic mixing system, theoil phase was added into the first inlet port at a flow rate of 20 gramsper minute and the water phase was added into the second inlet port at aflow rate of 3980 grams per minute. The oil phase and water phase weremixed in the chamber for a total of 30 seconds.

Sample 3 was prepared by additionally mixing in a surfactant(Solubilisant LRI, LCW, South Plainfield, N.J.) with the oil phase in aweight ratio of surfactant to oil of 1:1. The mixed oil phase (includingthe surfactant) was then added at a flow rate of 24 grams per minuteinto the first inlet port of the ultrasonic mixing system of FIG. 1. Thewater phase was added into the second inlet port at a flow rate of 3980grams per minute and mixed with the oil phase. The oil and surfactant ofthe oil phase and water of the water phase were added at a weight ratioof 0.3:0.3:99.4. Once the emulsions were formed, the emulsions werevisually inspected and stored in two separate containers. After 30hours, the containers were visually inspected. The results are shown inTable 3.

TABLE 3 Visual Observation Visual of Physical Observation Appearance ofPhysical of Emulsion Appearance Mixing Immediately of Emulsion MixingTime After after 30 Sample Method (min) Mixing hours 1 Hand mixer 2.0Milk-like Oil phase formulation completely for 1-2 separated minutesfrom water phase 2 Ultrasonic 0.5 Stable Milk-like mixing milk-likeemulsion system emulsion with a few 1 mm with no diameter droplets oildroplets on top; separated completely after 3 days 3 Ultrasonic 0.5Milk-like Milk-like mixing emulsion emulsion system without withoutvisible oil visible oil droplets droplets

As shown in Table 3, both of the emulsions produced using the ultrasonicmixing system remained stable until 30 hours after exiting the chamberwhile the emulsion prepare in the batch process separated within acouple minutes. While Sample 2 finally separated completely after about3 days, the emulsion prepared using the oil phase that comprisedSOLUBILISANT LRI remained stable for 40 days.

The oil droplets from the batch-produced oil-in-water emulsion weresized from several micrometers to several hundreds of micrometers. Forthe two emulsions produced using the ultrasonic mixing system, afterfive days of aging) the oil droplets ranged from sub-micrometers in sizeto a couple of micrometers.

When introducing elements of the present disclosure or preferredembodiments thereof, the articles “a”, “an”, “the”, and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including”, and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

As various changes could be made in the above constructions and methodswithout departing from the scope of the invention, it is intended thatall matter contained in the above description and shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

1. An ultrasonic mixing system for preparing an emulsion, the mixingsystem comprising: a treatment chamber comprising: an elongate housinghaving longitudinally opposite ends and an interior space, the housingbeing generally closed at at least one longitudinal end and having atleast a first inlet port for receiving a first phase for an emulsion, asecond inlet port for receiving a second phase for the emulsion into theinterior space of the housing, and at least one outlet port throughwhich the emulsion is exhausted from the housing following ultrasonicmixing of the first and second phases to form the emulsion, the outletport being spaced longitudinally from the first and second inlet portssuch that the first and second phases flow longitudinally within theinterior space of the housing from the inlet ports to the outlet port;and an elongate ultrasonic waveguide assembly extending longitudinallywithin the interior space of the housing and being operable at apredetermined ultrasonic frequency to ultrasonically energize and mixthe first and second phases flowing within the housing, the waveguideassembly comprising an elongate ultrasonic horn disposed at least inpart intermediate the first and second inlet ports and the outlet portof the housing and having an outer surface located for contact with thefirst and second phases flowing within the housing from the first andsecond inlet ports to the outlet port, and a plurality of discreteagitating members in contact with and extending transversely outwardfrom the outer surface of the horn intermediate the first and secondinlet ports and the outlet port in longitudinally spaced relationshipwith each other, the agitating members and the horn being constructedand arranged for dynamic motion of the agitating members relative to thehorn upon ultrasonic vibration of the horn at the predeterminedfrequency and to operate in an ultrasonic cavitation mode of theagitating members corresponding to the predetermined frequency and thefirst and second phases being mixed in the chamber.
 2. The ultrasonicmixing system as set forth in claim 1 further comprising a firstdelivery system operable to deliver the first phase to the interiorspace of the housing of the treatment chamber through the first inletport and a second delivery system operable to deliver the second phaseto the interior space of the housing of the treatment chamber throughthe second inlet port, wherein the first phase and second phase areindependently delivered at a rate of from about 1 gram per minute toabout 100,000 grams per minute.
 3. The ultrasonic mixing system as setforth in claim 1 wherein the emulsion is selected from the groupconsisting of oil-in-water emulsions, water-in-oil emulsions,water-in-oil-in-water emulsions, oil-in-water-in-oil emulsions,water-in-silicone emulsions, water-in-silicone-in-water emulsions,glycol-in-silicone emulsions, and high internal phase emulsions.
 4. Theultrasonic mixing system as set forth in claim 3 wherein the first phaseand second phase are independently selected from the group consisting ofan oil phase, a water phase, a silicone phase, a glycol phase, andcombinations thereof.
 5. The ultrasonic mixing system as set forth inclaim 4 wherein at least one of the first phase and second phase furthercomprise a surfactant.
 6. The ultrasonic mixing system as set forth inclaim 3 further comprising a third inlet port for receiving a thirdphase for the emulsion into the interior space of the housing, the thirdphase being selected from the group consisting of an oil phase, a waterphase, a silicone phase, a glycol phase, and combinations thereof. 7.The ultrasonic mixing system as set forth in claim 1 wherein thepredetermined frequency is in a range of from about 20 kHz to about 40kHz.
 8. The ultrasonic mixing system as set forth in claim 1 wherein thehorn has a terminal end within the interior space of the housing andsubstantially spaced longitudinally from the inlet port to define anintake zone therebetween within the interior space of the housing.
 9. Anultrasonic mixing system for preparing an oil-in-water emulsion, themixing system comprising: a treatment chamber comprising: an elongatehousing having longitudinally opposite ends and an interior space, thehousing being generally closed at at least one longitudinal end andhaving at least a first inlet port for receiving an oil phase into theinterior space of the housing, a second inlet port for receiving a waterphase into the interior space of the housing, and at least one outletport through which an oil-in-water emulsion is exhausted from thehousing following ultrasonic mixing of the oil phase and water phase toform the oil-in-water emulsion, the outlet port being spacedlongitudinally from the inlet port such that the oil and water phasesflow longitudinally within the interior space of the housing from theinlet port to the outlet port; an elongate ultrasonic waveguide assemblyextending longitudinally within the interior space of the housing andbeing operable at a predetermined ultrasonic frequency to ultrasonicallyenergize and mix the oil and water phases flowing within the housing,the waveguide assembly comprising an elongate ultrasonic horn disposedat least in part intermediate the first and second inlet ports and theoutlet port of the housing and having an outer surface located forcontact with the oil water phases flowing within the housing from thefirst and second inlet ports to the outlet port, a plurality of discreteagitating members in contact with and extending transversely outwardfrom the outer surface of the horn intermediate the first and secondinlet ports and the outlet port in longitudinally spaced relationshipwith each other, the agitating members and the horn being constructedand arranged for dynamic motion of the agitating members relative to thehorn upon ultrasonic vibration of the horn at the predeterminedfrequency and to operate in an ultrasonic cavitation mode of theagitating members corresponding to the predetermined frequency and theoil water phases being mixed in the chamber, and a baffle assemblydisposed within the interior space of the housing and extending at leastin part transversely inward from the housing toward the horn to directlongitudinally flowing oil and water phases in the housing to flowtransversely inward into contact with the agitating members.
 10. Theultrasonic mixing system as set forth in claim 9 further comprising afirst delivery system operable to deliver the oil phase to the interiorspace of the housing of the treatment chamber through the first inletport and a second delivery system operable to deliver the water phase tothe interior space of the housing of the treatment chamber through thesecond inlet port, wherein the oil phase and the water phase areindependently delivered to the interior space of the housing at a rateof from about 1 gram per minute to about 100,000 grams per minute. 11.The ultrasonic mixing system as set forth in claim 9 wherein the oilphase further comprises a surfactant.
 12. The ultrasonic mixing systemas set forth in claim 9 wherein the predetermined frequency is in arange of from about 20 kHz to about 40 kHz.
 13. The ultrasonic mixingsystem as set forth in claim 9 wherein the horn has a terminal endwithin the interior space of the housing and substantially spacedlongitudinally from the inlet port to define an intake zone therebetweenwithin the interior space of the housing.
 14. A method for preparing anemulsion using the ultrasonic mixing system of claim 1, the methodcomprising: delivering the first phase via the first inlet port into theinterior space of the housing; delivering the second phase via thesecond inlet port into the interior space of the housing; andultrasonically mixing the first and second phases via the elongateultrasonic waveguide assembly operating in the predetermined ultrasonicfrequency.
 15. The method as set forth in claim 14 wherein the firstphase and the second phase are independently delivered at a rate of fromabout 1 gram per minute to about 100,000 grams per minute.
 16. Themethod as set forth in claim 14 wherein the emulsion is selected fromthe group consisting of oil-in-water emulsions, water-in-oil emulsions,water-in-oil-in-water emulsions, oil-in-water-in-oil emulsions,water-in-silicone emulsions, water-in-silicone-in-water emulsions,glycol-in-silicone emulsions, and high internal phase emulsions.
 17. Themethod as set forth in claim 16 wherein the first phase and second phaseare independently selected from the group consisting of an oil phase, awater phase, a silicone phase, a glycol phase, and combinations thereof.18. The method as set forth in claim 16 further comprising delivering athird phase via a third inlet port into the interior space of thehousing, the third phase being selected from the group consisting of anoil phase, a water phase, a silicone phase, a glycol phase, andcombinations thereof.
 19. The method as set forth in claim 14 wherein atleast one of the first phase and the second phase are heated prior tobeing delivered to the interior space of the housing.
 20. The method asset forth in claim 14 wherein the first and second phases areultrasonically mixed using the predetermined frequency being in a rangeof from about 20 kHz to about 40 kHz.